Gear-testing machine



Dec. 8, 1925- J. LAESSKER GEAR TESTING MACHINE Filed Feb. 15. 1921 :2Sheets-Sheet 1 2; INVENTOB BY I A TTOR/VE Y J. LAESSKER GEAR TESTINGMACHINE Filed Feb. 15, 1921 2 Sheets-Sheet 2 uvvs/vron 81/ 5 ATTORNEYPatented Dec. 8,1925.

UNITED STATES PATENT OFFlCE.

' JEAN LaEssKEn, or ARBON, SWITZERLAND, ASSIGNOR T socmrn ANONYMEADOLPHE saunnn, or Anson, SWITZERLAND, A conronnr-Ion or *swrrznm LAND.

Application filed. February 15, 1921. Serial No. 44$,(i86.

fl '0 all whom it may concern Be it known that I, JEAN LAnssnnn, acitizen of the Kingdom of Sweden, and resident of Arbon, Switzerland,have invented a certain new and useful Improvements in Gear-TestingMachines, ofwhich the following is a specification.

This invention is an apparatus for testing and measuring of gear wheels,and may be used for the detecting and locating of any inaccuracies inthe curvature or form of the gear teeth as well as for determining thepitch circle radius and angle of engagement. j, In carrying out myinvention 1 provide a feeler which ismounted to contact with a workingface of a toothof the gear to be tested and has an operating facewhichmay correspond in position or in form or both. to a face of acomplementary accurately formed gear member. The feeler support and thegear, when in proper relative position, are given a relative rollingmovement the pitch circle of the gear, sothat feeler on .its support sothat it is yleldinglyheld against the gear tooth face, any relativemovement of the feeler in respect to its I tion and angle of one side 0the-face of a' 'tooth on anamaginary rack bar with which '45 the gearwould "properly mesh. The relativerolling' movement of the gear and theimaginary rack bar and along the pitch circle thus causes the straightedge of the feeler to contact with successive portions of the surface ofthe tooth.

, As is well known,- the relative rolling along the eeler contacts withsuccessive portions support during such relative rolling move circleradius of a gear;

7 GEAR- TESTING MACHINE.

movement of a gear and acoacting gear member, such as a rack bar, may beaccomplished in three main ways :-first the rolling of the gear alongthe stationary rack, second, endwise movement of the rack and rotationof the gear about a stationary axis, and third, the rolling of the rackalong'the periphery of the gear while holding the latter stationary.Although any one of these three, or combinations of such movements mightbe imparted to the feeler support and the gear to be'tested, and arewithin the broad scopeof my invention, I preferably use the first ofthese ways of obtaining relative rolling movement. I preferably hold thefeeler support stationary during the testing, and roll the gear past itso that the indicator operated by the feeler. may be more easilyobserved and any slight movement of the indicator noted.

As one important feature of my invention I provide means whereby thedesired rolling movement may be given to the gear to be tested withoutnecessitating the provision of interchangeable parts for gears ofdifferent pitch circles, or different number or angle ofengagementbf thegear teeth.

This is preferably accomplished by securing radius, and moving the axisof the gear and said member in one direction while moving a peripheralpart of the member in the opposite-direction. The ratio of the rates ofsuch movements may be varied in" accordance with the ratio of the radiiof the gear pitch circle and of said member. By making this simpleadjustment the apparatus may be used for testing gears of variousdifferent pitch circle radii.

As another: important feature I provide means whereby the adjustment maybe easily and quickly made for a gearofknown pitch circle radius ormaybe adjusted to measure and determine the unknown pitch As anotherimportant feature l so mount the feeler support that it may be easilyand quickly adjusted for gears of different pitch circle radius and forgears having different numbers of teeth and different angles of toothengagement. This adjusting means drawings, in which is also so designedthat it may be used for determining the unknown tooth angle of a givengear.

As a further important feature, the feelcr 5 is so designed and somounted that it may be used for the testing of either of the oppositeworking faces of a gear tooth, and may be easily shifted to either sideof the tooth and set at the required angle without u disturbing otheradjustments of the ap' paratus.

Various other features of importance are incorporated in a preferredembodiment of my invention shown in the accompanying Figure 1 is a faceview of an apparatus embodying my invention, and

Figure 2 is a perspective view of a slightly modified form parts beingbroken away.

In the form illustrated there is provided a main fram 10, serving tosupport two slides 11 and 12, movable in accurately formed guides, onecarrying the gear to be tested 25, and the other carrying the feeler.The slide 11 is provided with a stud 13 or other part upon which may bemounted the gear, a to be tested. The gear is clamped rigid with.

the stud by any suitable means not shown.

In connection with the slide 11, I employ means for giving the gear arolling movement along its pitch circle during the reciprocation of theslide 11, and irrespective of the radius of the pitch circle. This meansis shown as including an arm 14, rigidly securedto the stud 13, andthrough it to the 5 16 terminate in bearing surfaces 17 and 18 restingon anti-frictionalrollers 19 and 20 carried by a lever 21 normally atright angles to the direction of movement of the slides 11 and 16, andhaving a fulcrum 22 intermediate of its ends. Thus, as the slide 11 ismoved in one direction the lever 21 is moved about its fulcrum and theslide 16 will move in a direction opposite to that of the slide 11. Itwill be noted that the axis 5 of the roller 20 with which the slide 16engages is in the plane ofthe working face of the slide 16, and that theaxis of the roller 19 is opposite to the axis of the'gear in thedirection of movement of the slide 11.

Therefore, if the distance between the axis of the roller 19 and thefulcrum point 22 of the lever 21 and indicated by the line A on Fig. 1be equal to the pitch circle radius of the gear-to be tested, the bodilymovement of the slide 11in either direction from the position shown,will cause such a reverse movement of the slide=l6 as will cause thegear to rotate while moving laterally with the slide 11, and thisrotation will be at the same rate as would result from the movement ofthe gear along an accurately formed rack. 'In effect the arm 14 willoscillate about the point of intersection of its radius normal to theslide 16 and the pitch circle of the gear.

It the gear being tested have a pitch radius equal to the radius of thesegment 15, the fulcrum would be adjusted to a position opposite theaxis of the roller 20 and the slide 16 would remain at rest during therolling movement of the gear. 1f the gear have a pitch radius largerthan that of the segment, the fulcrum would be moved to the properdistance above the lower side of the slide 16, and both the slides 11and 16 would move in the same direction but at different rates duringthe rolling movement of the gear.

In order to accommodate the apparatus to gears of different pitch circleradii, the fulcrum point is adjustable lengthwise of the lever 21. Asshown in Fig. 1, this fulcrum is a pivot pin connecting a pair ofbearing numbers 23 and 24, one slidable along the frame of the machineand the other slidable along the lever 21. The movement of these bearingmembers and the fulcrum pin may be accurately controlled and the partsheld in adjusted position by a pair of screws 25 and 26 threaded to thebearing members. One of the slides as for instance the slide 11, isprovided with means for manually moving it endwise in either directionat a slow and controlled rate, such means being illustrated as a screw27 with an operating handle 28. The other slide, 16 is provided with acoil spring 29 for holding both slides in proper operating engagementwith the lever 21. a

The lever 21 is preferably provided with a scale, the zero point ofwhich is opposite to the axis of the gear to be tested, and preferablythe scaleis calibrated to directly show the pitchcircle radius of thegear to: be tested. Thus the position of the bearing member 24 and thedistance of the fulcrum from the zero'point of the scale may be easilyread. If this radius of the gear is known, the fulcrum point 22 isadjusted lengthwise of the scale to the point indicating this knownradius.

Any suitable means may be provided for guiding the slide 16 during itslongitudinal movement, but preferably I employ pairsof guiding rollers30 and 31, and spring means 31 for holding the slide in frictionalengagement with the segment 15.

The guide rollers 30 and 31 are carried by Ion Ill)

supports which are slidably mounted in the main frame, and movable in adirection at its axis and over the dial.

right angles to the path of movement of the ing the nuts the springsmove the-supports.

inwardly endwise, and resiliently press the slide against the segment.For lifting. the slide off the segment to facilitate the properadjustment of the parts upon the insertion of the gear to be tested, Iprovide an eccentric 32.

The slide 12 which is movable in a direction at right angles to theslides 11 and 16, carries the indicator and indicator operating memberor feeler, and the means for adjusting the latter to gears of differentdiameters, gear teeth of different depth,

and gear teeth faces of different angles of engagement. Asshown, theslide 12 is adjusted by means of a threaded rod and nut34 and carries asupport 35 mounted to swing in a plane parallel to the plane of theslides 11 and 16, and'about a pivot pin or axis 36. Mounted in thissupport 35 is a sliding plunger member 37 having a feeler 38, adapted toengage with the working face of the gear tooth to be tested. The plungermember 37 is pressed in one direction by a helical spring 39, so as toyieldingly hold the feeler against the gear tooth and-by a locking screw40 the feeler is held fast in .the plunger member 37.

The support 35 also carries an indicator. Merely for purposes ofillustration, I have shown such indicator in the form of a dial 41 witha pointer 42 having operative connections with the slide 37 whereby asthe slide moves endwise in respect to the-sup port, the pointer iscaused to swing about The details of such connections form no portion ofmy invention, and may be varied at will.

'Theslide 12 carries a graduated are 43 and the support 35 has a pointer44 properly juxtaposed to the scale on the are. Both the support .35 andthe graduated are 43 are carried by the slide 12 and the support 35 maybe clamped to the are many desired angular adjustment about the pivot36, by

means of. one or more clamping members 45. The seale'on the arc isgraduated to read directly the angle of engagement of the tooth face,and the feeler 38 projects in opposite directions from the support sothat either end maybe brought into operation.

As shown, one end is in engagen'ient with the left hand side of a geartooth, but by swinging the support 35 clockwise through the properangle, the opposite end of the feeler may be brought against the otherside of the gear tooth, and the pointer 44 will come adjacent to anothersection of the scale, also directly indicating the angle of engagementof the tooth face.

In Figure 2 I have shown a device very similar in most respects to thatshown in Figure 1, except that the parts are more diagrammaticallyillustrated and in perspective, and many parts are broken away. Asomewhat different mechanism for adjusting the position of the leverfulcrum is shown. A slide carries a spindle 22 upon the upper end ofwhich there is provided a block 51. This slide 50 may be-adjusted in thedirection of the length of the lever bymeans of a threaded rod '52operated by the handle 26. The lever 21 isprovided with a threaded rod53 which engages in block 51.

By rotating this-threaded rod'by means of the crank 25 the lever may bemoved endwise in the block 51. The position of the spindle 22 determinesthe pivotal center or fulcrum of the lever, and this may be moved to anydesired position by the handle 26. Either during the shifting of theposition of the fulcrum or after it has been shifted,

the-crank 25 is turned in the proper direc tion to hold or bring therollers 19 and 20 in proper position in respect to the hearing surfaces17 and 18 on the ends of the slides 11 and 16.

-44 is opposite the known angle of engagement of the tooth face. Theslide 12 is adjusted toward the gear. until the feeler 38 enters to theproper distance between the gear teeth, the slide 16 being raised. Theposition of the pointer 42 on the dial 41 is then noted, the slide 16 isthen lowered by the eccentric 32 on the segment and the handle 28 isthen slowly rotated in either,

or alternately in both directions. As the slide 11 moves endwise, thegear axis will be moved bodily and the action of the lever 21, slide 16,and arm 14 will be such as will cause a turning of the gear about itsaxis. Theresulting movement of the gear is thus a true rolling movementof the gear on its pitch circle. The feeler 38 has its roll.

straight face at the angle and in the position of a face of an lmaginaryrack bar along which the gear may be assumed to- Thus, if'the workingface of the gear be perfect in form and free from any irregularities therolling movement of the gear will not produce any movement whatsoever ofthe feeler 38, and the pointer 42 will remain at rest. If there is anyirregularity in the formation of the tooth face it will cause or permitan endwise movement of the slide 37 with the feeler, and this will beindicated by the pointer 42. The exact portion of the gear face which isin contact with the feeler during such movement .of the pointer may benoted, as well as the direction of movement of the pointer. Thus thecharacter and location of the inaccuracy or irregularity in the gearface will be shown.

Each tooth may be separately tested, and

the opposite face may be tested by swinging the support to bring theother end of the feeler into position. 3

If the pitch radius of the gear is known but the angle of engagement ofthe gear teeth is to be determined, the gear will be secured in positionas before, and the fulcrum is adjusted to the proper pitch radius. Theoperator guesses at" the approximate tooth angle and sets the support35' accordingly. This adjustment is altered with successive rollingmovements of the gear until the proper position is reached at whichthere is no movement of the pointer 42, assuming the gear face be freefrom inaccuracy. The reading of the pointer 44 will' then give the toothangle. If the tooth be slightly inaccurate, the support 35 is adjusteduntil the pointer 42 gives the same reading with the feeler at theoutermost and innermost portions of the side of the tooth.

If the angle is known but the pitch radius is to be determined, thesupport 35 is set with its pointer 44 at the proper position on thegraduated are 43, and, the fulcrum 22 adjusted back and forth until thepointer 42 remains stationary during the rolling movement of the gear,or at least is stationary when the feeler is at the outermost andinnermost portions of the tooth face.

If neither the pitch radius nor the tooth angle is known," both "ofthese are estimated and the proper adjustments of the fulcrum and feelerare made. By continuing the adjustment and giving the gear its rollingmovement for each adjustment the proper pitch radius and tooth angle maybe eventually determined.

As has previously been pointed out, various other means might beemployed for giving to the gear its rolling movement along its pitchcircle or in respect to a cooperating imaginary rack.

The slide 12 is shown as movable at a circle.

right angle to and in a plane parallel to slides 11 and 16 for testingspur gears. Appropriate'ehange can be made in the frame so as to givethe proper direction and angle of movement and relationship of the partsfor testing helical, bevel or other forms of gears. I have referred tothe rolling of the gear on its pitch circle, but for some special gearsthe rolling might be on some other As the apparatus tests only one toothat atime, it is equally applicable to to testing gear segments Which'Iinclude in the broad term of gear.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. An apparatus for testing gears, including a support for the gear tobe tested, a member having straight line back and forth movement in aplane at right angles to the axis of the gear support, a feeler carriedthereby and adapted to engage a working face of a tooth of the gear heldon said support, means for effecting a relative rolling movement of saidfeeler and said gear, and means acting on said member for holding saidfeeler in yielding engagement with the tooth. face during said rollingmovement.

2. An apparatus for testing gears, including a support for the gear tobe tested,

a feeler adapted to engage a working face of the gear held on saidsupport, a guiding support for said feeler permitting straight line backand forth movement of the feeler in respect to the support, yieldingmeans pressing said feeler in one direction of said straight line,movement and resisting but permitting movement in the opposite directionin respect ot said second mentioned support, and means for effecting arelative rolling movement of one support in respect to the other.

3. An apparatus for testing gears, including a support for the gear tobe tested, a feeler adapted to engage a working face of the gear held onsaid support, a guiding support for said feeler permitting straight lineback and forth movement of the feeler in respect to the support and in adirec- .tion substantially tangential to the pitch circle of said gear,yielding means pressing said feeler 1n one direction of said straightline movement and resisting but permitting movement in the oppositedirection in respect to said second mentioned support, a support forsaid feeler, said feel for yieldingly holding said er having straightline back and fortli'movement in respect to said second mentionedsupport, yielding means for resisting said movement in one direction,and means forv efl'ecting. a relative rolling movement of one support inrespect to the other.

5. An apparatus for testing gears, including a gear support, means formoving said support in a direction at right angles to the axis of thegear support, and imparting to' said gear a rolling movement along itspitch circle, and a feeler having a straight line operating facecorresponding in normal position and angle to an imaginary rack bartooth meshing with said gear. w 6. An apparatus for testing gears,including a gear support, a feeler, a feeler support mounted for back.and forth straight line movement in a plane at right angles to the axisof the gear su port, means eeler in engagement with ,the 'working faceof a tooth of a gear held on said gear support, and means for rollingsaid gear along its pitch circle. I

7. An apparatus for testing gears, including a member presenting acurved surface, and mounted to oscillate'about the center of curvature,and adapted to receive the gear to be tested with its pitch circleconcentric with said curved surface, and

means formoving the axis of the gear held on said member in onedirection and said curved surface in the opposite direction, whereby arolling movement is imparted to said gear. f i

8. An apparatus for imparting a rolling movement to a gear, including amember presenting a curved surface, and adapted to carry the gear to betested with its pitch circle coaxial I with said curved surface,

and means for moving the axis of said gear in one direction'and saidcurved surface in the opposite direction.

9. An apparatus of the character defined in claim 8, havi g means forvarying the relative rates of movement of said axis and curved surface.

10. An apparatus 'for imparting. a roll ing movement to a gear,including a member having a segment, and adapted to supv portthe gear tobe tested with its pitch circle coaxial with said segment, and means foroscillating said member about the point,

, of intersection of a radius of said segment and the pitch circle ofthe gear supported by said member. v

11. An'apparatus as defined in claim 10 having means for varying thecenter of oscillation of said member in accordance with the pitch circleradius of the gear.

12. An apparatus for imparting a rolling movement to a gear, includinga. member adapted to carry the gear to be tested and having a curvedsegment coaxial-with the. itch circle of said gear, and a lever pivotedintermediate of its ends and, operatively connected to said member formoving the ear axis in one direction and said segment in the oppositedirection.

13. An apparatus for imparting a rolling movement to a gear, including amember having a curved segment and adapted to be rigidly connected'tothe gear to be tested with the pitch circle of the gear coaxial witlrvmember for moving the gear axis in one direction and said segment in theo posite direction,- and means for adjusting t e fulcrum' point of thelever along the length of the latter. a

said segment, a lever pivoted intermediate; of its ends and operativelyconnected to said 14. An apparatus for imparting a rolling movement to agear, including a slide, a

member pivoted in said slide, and presenting a curved segment, adaptedto carry the gear to be tested with its axis-coincident with the axis ofsaid segment, a slide parallel to said first mentioned slide andengaging with said curved segment, and means for moving one of saidslides in one direction and the other in the opposite direction.

15. An apparatus for imparting a rolling movement to a ear, including aslide, a

one of said slides in one direction and th 7 other in the oppositedirection.

16. An apparatus for imparting a rolling movement to a gear, including aslide, a

member pivoted thereto and presenting a curved segment rigid withthegear to be member pivoted t ereto presenting a curved testedand withits axis. coincident with the v axis of said gear, a slide parallel tosaid first mentioned slide'and engagin with said curved segment, a leverfor moving one of said'slides in one direction and the other in theopposite direction, and means for varying the position of the fulcrumpoint of the lever in accordance with the pitch-radius of the gear to betested. I

17. An apparatus for imparting a rolling movement to a gear, including apair of parallel slides, a gear supportin member pivotally connectedtoone side an havinga curved surface concentric with the gear andengaging.with the other slide, a lever pivoted intermediate of its ends andengagmg with both of said slides, and having a scale thereon, and meansfor adjusting the fulcrum of the lever along the latter. to apoint onthe. scale corresponding to the pitch I radius of said gear. 18. Anapparatus fortestin gears, includmg means for ..parting a re imgmovement a face adapted to engage with the face of a tooth of said gear,and a support for said feeler, said support being angularly adjustableto vary the angle of engagement of the face of the feeler with the faceof the gear tooth. I

20. An apparatus for testing gears, ineluding areeiprocatory slide,means for mounting the gear thereon, means for imparting a rollingmovement to said gear during a reciprocation of the slide, a secondslide substantially at right angles to the first mentioned slide, afeeler support carried by said second mentioned slide, and a feelerieldingly mounted on said support.

21. n apparatus for testing gears, including a reciprocatory slide,means for mounting the gear thereon, means for imparting a rollingmovement to said gear during a reciprocation of the slide, a secondslide substantially at right angles to the first mentioned slide, afeeler support carried by said second mentioned slide, a feelerresiliently mounted on said support and means for adjusting said supportangularly in respect to said second mentioned slide.

22. An apparatus for testing gears, including a support for the gear tobe tested, means for imparting a rolling movement to said gear, a feeleradapted to engage with a tooth of the gear, a slide carrying saidfeeler, a guide for said slide, yielding means acting on said slide tohold the feeler against the gear tooth, and an indicator op-v eratingupon relative and support.

23. An apparatus for testing gears, including a support for the gear tobe tested, means for imparting a rolling movement to said gear, a feelerpresenting an edge for engagement with a tooth face, a feeler carrier, asupport for said carrier and permitting of the reciprocation of thecarrierdur movement of the slide ing rolling movement of the gear, andan indicator operated upon suchreciprocation.

24. An apparatus for testing gears, including a suppbrt for the gear tobe tested, a feeler presenting a straight edge, a feeler carrierengaging the feeler intermediate of the ends, and a pivotal support forsaid carrier permittingit to move in opposite positions to bring one endof said feeler into engagement with one face of a tooth of said gear orthe opposite end of the feeler into engagement with the opposite face ofsaid tooth. b

25. An apparatus for testing gears, in-

cluding a reeiprocatory slide, guiding means therefor, means formounting a gear on said slide, means for imparting a rolling movement tosaid gear during reciprocation of theslide, a second reciprocatoryslide, guiding means therefor, and a feeler carried thereby and adaptedto engage with the working fare of av tooth of the gear, one of saidguiding means being angularly adjustable in respect to the other to varythe direction of movement of the second mentioned slide in respect tothe direction of movement of the first mentioned slide.

26. An apparatus for testing gears, including a slide, means formounting a gear thereon, means for imparting a rolling movement to saidgear during reciprocation of the slide, a second slide, a feeler carriedthereby and adapted to engage with the working face of a tooth of thegear, and means for bodily adjusting said second mentioned slide towardand from the first mentioned slide.

27. An apparatus for testing gears, in cluding a slide adapted tosupport the gear to be tested, a second slide moveable in the directionat right angles to the direction of movement of the first mentionedslide, a third slide carried by the second mentioned slide and angularlyadjustable in respect to the latter, and a feeler carried by the thirdmentioned slide and adapted to engage with a face of a tooth of saidgear.

28. An apparatus of the class described, including a feeler presenting astraight edge, a support for holding said edge in position and anglecorresponding to a tooth face of an imaginary rack bar, means for.

rolling the gear to be tested along said imaginary rack bar, yieldingconnections between said feeler and said support, and an indicatorshowing the relative movement of the feeler and support, correspondingto irregularities or inaccuracies of the tooth face of said gear withwhich the fecler engages.

29. An apparatus for testing gears, including means for imparting arolling movement to the gear to be tested and along its pitch circle, afeeler presenting a straight edge and corresponding to a face of a toothof an imaginary rack bar meshing with the gear to be. tested, a supportfor said feeler, yielding connections between said support and saidfeeler, means for adjusting the position of the support in accordancewith the radius and tooth angle of the gear to be tested, and anindicator operating upon relative movement of the feeler and itssupport, and showing their-regularities or inaccuracies of the toothface with which the feeler engages during the rolling movement of thegear. I

' 30. An apparatus for testing gears, in-

cluding a support for the gear to be tested,

gagement with the tooth of the gear to be tested, a feeler carrier, asupport for said 1 carrier and permitting of the reciprocation of thecarrier, an indicator operating upon suchreciprocation, and means forimparting a' relative rolling movement to said gear and said carriersupport. K 31. An apparatus for testing gears, including a support forthe gea" to be tested, a feeler, a feeler carrier, rift ans forsupporting said carrier with one end of said feeler in engagement withone face of a tooth of said gear, or with the opposite end of the feelerin engagement with the oppo site face of said tooth, and means foreffecting a relative rolling movement of said gear and said feeler.

32. An a paratus for testing gears, in-

- eluding a eeler adapted to yieldingly engage with the working face ofa tooth of the gear to be tested, a support for said feeler,

'means for adjusting said support toward and from the axis of said gear,means for permitting adjustment of said support to var the angle ofengagement of the feeler wit the tooth face, and means for effectinggear a relative rolling movement of; the and feeler.

33. An apparatus for imparting a rolling movement to a gear, including agear supporting member having a segment concentric with the pitch circleof the gear, means for oscillating said member about the point ofintersection of a radius of said segment and the pitch circle of thegear held by said supporting member, and at the same time moving sa1dpoint in a direction tangential to said pitch circle.

.. 34:. A gear testing apparatus including a.

support or the gear to be tested, a feeler having a pair of contactfaces, a feeler car rier, a pivotally mounted support inwhich saidcarrier may reciprocate, means for normally holding said secondmentioned supportfagamst pivotal movement, and means .for holding saidsecond mentioned support with one. face of said feeler againstone faceof a gear tooth, of a gear held'by said support, or the other face ofthe feeler against the op osite face of the gear tooth.

. support 35. gear'testing apparatus including aor thegear to be tested,a feeler having a pain of contact faces, a feeler carrier, apivotallyqnounted support in which said carrier may reciprocate, meansfor normally holding sald second mentioned support aga nst pivotalmovement means for holding said second mentioned support with one faceof said feeleragainst one face of a gear tooth of agear'held by saidsupport, or the other face ofthefeeler against the opposite face ofv thegear tooth, and an indicator operated by the relative movement of saidcarrier and said second mentioned support during a relative, rollingmovement of one support in respect to the other. 36. ear testingapparatus including a support or the gear to be tested, a slideadjustable radially of the axis of the gear,

.a support pivoted. thereon to swing about an axis parallel to butspaced from the axis ofthe gear held by said support, means for normallyholding said second mentioned support against pivotal movement, a feelercarrier mounted on said last mentioned support for reciprocationradially of the see-l 0nd mentioned axis, and a feeleron said carrier. a37 A gear testing apparatus including a support for the gear to betested, a second support pivoted to swing about an axis carried by saidfee er support and resilient means tending to move said carrier andfeeler in one direction along said path and to hold said feeler inengagement with the surface of ,a tooth ofthe gear to'be tested.

39. A gear testing apparatus including a gear support, means for movingit in a direction at right angles to the axis of a" gear held by saidsupport, means for simulof said movements.

41. A gear testing apparatus including a gear support having a curvedsurface of xed radius and concentric with the pitch circle of thegearheld by said support and to be tested, a member having rolling contact w1th said surface, means for moving said member endwise during arolling movement of said. gear supportalong said member, and means forvarying the relative rates of said movements.

42. A gear testing apparatus including a gear support having a curvedsurface of 'fixed radius and concentric with the pitch circle of thegear held by said support and taneously moving it angularly about theIII to be tested, a member having rolling contact with said surface, andmeans for recip rocating said member in one direction during a rollingmovement of said gear support along said member in the oppositedirection.

43. A gear testing apparatus including a gear support having a curvedsurface of fixed radius and concentric with the pitch circle of the gearheld by said support and to be tested, a member having holding contactWith said surface, means for rolling said surface along said member, andmeans for simultaneously moving said member in a direction parallel tosaid surface.

Signed at St. Gallin, Switzerland this 19th day of January, A. D. 1921.

JEAN LAESSKER.

